Polycarbonate (PC), a tough, transparent synthetic resin employed in safety glass, eyeglass lenses, and compact discs, among other applications. PC is a special type of polyester used as an engineering plastic owing to its exceptional impact resistance, tensile strength, ductility, dimensional stability, and optical clarity. It is marketed under trademarks such as Lexan and Makrolon.

PC was introduced in 1958 by Bayer AG of Germany and in 1960 by the General Electric Company of the United States. As developed by these companies, PC is produced by a polymerization reaction between bisphenol A, a volatile liquid derived from benzene, and phosgene, a highly reactive and toxic gas made by reacting carbon monoxide with chlorine. The resultant polymers (long, multiple-unit molecules) are made up of repeating units containing two aromatic (benzene) rings and connected by ester (CO-O) groups.